Revert "LU-12328 flr: preserve last read mirror"

This is causing somewhat frequent crashes tracked in
LU-12525

This reverts commit 810f2a5fef577b4f0f6a58ab234cf29afd96c748.

Change-Id: If7604ad4ca1d4ddc63a20fa2ec7d9467ee7bb5f9
Reviewed-on: https://review.whamcloud.com/35450
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/lov/lov_cl_internal.h b/lustre/lov/lov_cl_internal.h
index 7249f88..a72d455 100644 (file)
--- a/lustre/lov/lov_cl_internal.h
+++ b/lustre/lov/lov_cl_internal.h
@@ -312,15 +312,8 @@ struct lov_object {
                         */
                        int             lo_preferred_mirror;
                        /**
-                        * The last mirror that has been read successfully.
-                        * This field is maintained so that subsequent read
-                        * can take the advantage of last retries and avoid
-                        * reading some unavailable OSTs.
-                        */
-                       int             lo_last_read_mirror;
-                       /**
                         * For FLR: the lock to protect access to
-                        * lo_last_read_mirror.
+                        * lo_preferred_mirror.
                         */
                        spinlock_t      lo_write_lock;
                        /**

diff --git a/lustre/lov/lov_io.c b/lustre/lov/lov_io.c
index 415a91b..2fa95f5 100644 (file)
--- a/lustre/lov/lov_io.c
+++ b/lustre/lov/lov_io.c
@@ -390,31 +390,15 @@ static int lov_io_mirror_init(struct lov_io *lio, struct lov_object *obj,
            /* reset the mirror index if layout has changed */
            lio->lis_mirror_layout_gen != obj->lo_lsm->lsm_layout_gen) {
                lio->lis_mirror_layout_gen = obj->lo_lsm->lsm_layout_gen;
-               index = lio->lis_mirror_index = comp->lo_last_read_mirror;
+               index = lio->lis_mirror_index = comp->lo_preferred_mirror;
        } else {
                index = lio->lis_mirror_index;
                LASSERT(index >= 0);
 
                /* move mirror index to the next one */
-               spin_lock(&comp->lo_write_lock);
-               if (index == comp->lo_last_read_mirror) {
-                       do {
-                               index = (index + 1) % comp->lo_mirror_count;
-                               if (comp->lo_mirrors[index].lre_valid)
-                                       break;
-                       } while (index != comp->lo_last_read_mirror);
-
-                       /* reset last read replica so that other threads can
-                        * take advantage of our retries. */
-                       comp->lo_last_read_mirror = index;
-               } else {
-                       /* last read index was moved by other thread */
-                       index = comp->lo_last_read_mirror;
-               }
-               spin_unlock(&comp->lo_write_lock);
+               index = (index + 1) % comp->lo_mirror_count;
        }
 
-       /* make sure the mirror chosen covers the extent we'll read */
        for (i = 0; i < comp->lo_mirror_count; i++) {
                struct lu_extent ext = { .e_start = lio->lis_pos,
                                         .e_end   = lio->lis_pos + 1 };

diff --git a/lustre/lov/lov_object.c b/lustre/lov/lov_object.c
index 632a4d3..ae535c0 100644 (file)
--- a/lustre/lov/lov_object.c
+++ b/lustre/lov/lov_object.c
@@ -783,7 +783,6 @@ static int lov_init_composite(const struct lu_env *env, struct lov_device *dev,
        }
 
        LASSERT(comp->lo_preferred_mirror >= 0);
-       comp->lo_last_read_mirror = comp->lo_preferred_mirror;
 
        EXIT;
 out: